I give unto thee: the greatest Prince story you have never heard (just in time to see Prince on Friday and Saturday at the Hard Rock Hotel).

This story comes from Matt “Doctor” Fink, Prince’s keyboardist from 1978 to 1990. Now Fink plays in The Purple Xperience, “the world’s premier Prince tribute band.” Someone in Vegas needs to book them.

Anyway, back in the fall of 1979, Prince and the Revolution went on tour for the first time as Rick James’ opening act. They were excited.

“None of us had ever done anything like that before,” Fink tells me by phone from Minneapolis.

So one day, Fink suggested it would be cool if Prince used a police megaphone as a stage prop. Prince agreed.

The next day, the band boarded a plane in Memphis to join James in Huntsville, Ala. And wouldn’t you know it — Fink noticed the plane had an emergency bullhorn in an overhead bin. He pointed it out to Prince, who said, “Really? Well, grab it. ... We should take this and use it onstage.”

Fink talked guitarist Dez Dickerson into stashing the bullhorn in his carry-on bag. But a passenger ratted them out while the plane idled on the tarmac.

“The next thing we know, the pilot comes out and announces, ‘It has come to our attention someone has removed some emergency equipment from the airplane, which is a federal offense,’ ” Fink recalls.

Prince admitted it was his idea. Both Prince and Fink were carted off the plane and held by airport police. And then?

“The Memphis police show up, handcuff us together and put us in the back of a squad car and drive us downtown to the Memphis jail,” Fink says and laughs. “They book us and put us in a holding cell — the kind that’s filthy, smelly, graffiti-ridden — a holding cell that common drunks and criminals are put into.”

Remember, this was 1979. Prince wasn’t famous yet. Fortunately, R&B radio stations just started playing his first hit R&B classic, “I Wanna Be Your Lover.”

So they were in jail.

“And some girl dressed in a police uniform walks up to the holding cell and looks at us through the window and she goes, ‘What’ch’all doing there? How come you guys are in there? Who are you guys?’

“Prince goes, ‘I’m Prince ... and this is the keyboard player from the band, Dr. Fink.

“And she goes, ‘You’re Prince! Prince, Prince! THE Prince?”

Thanks to that police fan, other cops got excited. Then the Revolution’s tour manager was able to talk the pilot into not pressing theft charges, on one condition.

“We were never to be allowed to fly on that airline,” Fink says. “I think it was called North Central Airlines, which was later bought out by Northwest ... and now Delta.”

The tour manager charted a scary little twin-engine, unpressurized Beechcraft plane to fly them to Huntsville.

“And of course, we had to fly every other airline except for North Central Airlines, going forward after that, because they wouldn’t let us fly.”

Fink says Prince really is a genius in the realm of Mozart.

Meanwhile, Fink’s cover band (ThePurplExperience.com) has been looking into Vegas gigs. They use costumes identical to Prince’s in the 1980s and play the hits.

“We really know how to present the music in an authentic way,” says Fink, who co-wrote the songs “Dirty Mind,” “It’s Gonna Be A Beautiful Night,” “Computer Blue,” “America” and “17 Days.”

What about Prince?

“He is really funny,” Fink says. “He’s fun to hang out with.”

Doug Elfman’s column appears Mondays, Tuesdays, Thursdays and Saturdays. He also writes for Neon on Fridays. Email him at delfman@reviewjournal.com. He blogs at reviewjournal.com/elfman.